Sulfuryl chloride
Encyclopedia
Sulfuryl chloride is an inorganic compound with the formula SO2Cl2. At room temperature, it is a colorless liquid with a pungent odor. Sulfuryl chloride is not found in nature, as can be inferred from its rapid hydrolysis
.
Sulfuryl chloride is commonly confused with thionyl chloride
, SOCl2. The properties of these two sulfur oxychlorides are quite different: sulfuryl chloride is a source of chlorine
whereas thionyl chloride is a source of chloride
ions. An alternative IUPAC name is sulfuroyl dichloride.
of the sulfur atom is +6, as in H2SO4.
and chlorine
in the presence of a catalyst, such as activated carbon
.
The crude product can be purified by fractional distillation
. It is uncommon to prepare SO2Cl2 in the laboratory because it is commercially available. Sulfuryl chloride can also be considered a derivative of sulfuric acid.
gas and sulfuric acid
:
SO2Cl2 will also decompose
when heated to or above 100 °C, about 30 °C above its boiling point.
Upon standing, SO2Cl2 decomposes to sulfur dioxide
and chlorine
, which gives the older samples a slightly yellowish color.
in the conversion of C-H → C-Cl adjacent to activating substituents such as carbonyls and sulfoxides. It also chlorinates alkane
s, alkene
s, alkyne
s, aromatics, and epoxide
s. Such reactions occur under free radical conditions using an initiator such as AIBN. It can also be used to convert disulfide
s into their corresponding sulfenyl chloride
s. SO2Cl2 can also convert alcohol
s to alkyl chlorides. In industry, sulfuryl chloride is most used in producing pesticides.
SO2Cl2 can also be used to treat wool to prevent shrinking.
. As described above, it can form explosive mixtures with water, as well as donor solvents such as DMSO
and DMF
.
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
.
Sulfuryl chloride is commonly confused with thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
, SOCl2. The properties of these two sulfur oxychlorides are quite different: sulfuryl chloride is a source of chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
whereas thionyl chloride is a source of chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
ions. An alternative IUPAC name is sulfuroyl dichloride.
Structure
Sulfur is tetrahedral in SO2Cl2, being bound to two oxygen atoms via double bonds and to two chlorine atoms via single bonds. The oxidation stateOxidation number
In coordination chemistry, the oxidation number of a central atom in a coordination compound is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom. Oxidation numbers are often confused with oxidation states.The...
of the sulfur atom is +6, as in H2SO4.
Synthesis
SO2Cl2 is prepared by the reaction of sulfur dioxideSulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
in the presence of a catalyst, such as activated carbon
Activated carbon
Activated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions.The word activated in the name is sometimes replaced...
.
- SO2 + Cl2 → SO2Cl2
The crude product can be purified by fractional distillation
Fractional distillation
Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation...
. It is uncommon to prepare SO2Cl2 in the laboratory because it is commercially available. Sulfuryl chloride can also be considered a derivative of sulfuric acid.
Reactions
Sulfuryl chloride reacts with water, releasing hydrogen chlorideHydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
gas and sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
:
- 2 H2O + SO2Cl2 → 2 HCl + H2SO4
SO2Cl2 will also decompose
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
when heated to or above 100 °C, about 30 °C above its boiling point.
Upon standing, SO2Cl2 decomposes to sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
, which gives the older samples a slightly yellowish color.
Uses
Sulfuryl chloride is often used as a source of Cl2. Because it is a pourable liquid, it is considered more convenient than Cl2 to measure, store, and dispense. SO2Cl2 is widely used as a reagentReagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
in the conversion of C-H → C-Cl adjacent to activating substituents such as carbonyls and sulfoxides. It also chlorinates alkane
Alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
s, alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s, alkyne
Alkyne
Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
s, aromatics, and epoxide
Epoxide
An epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...
s. Such reactions occur under free radical conditions using an initiator such as AIBN. It can also be used to convert disulfide
Disulfide
In chemistry, a disulfide usually refers to the structural unit composed of a linked pair of sulfur atoms. Disulfide usually refer to a chemical compound that contains a disulfide bond, such as diphenyl disulfide, C6H5S-SC6H5....
s into their corresponding sulfenyl chloride
Sulfenyl chloride
A sulfenyl chloride is a functional group with the connectivity R-S-Cl, where R is alkyl or aryl. Sulfenyl chlorides are reactive compounds that behave as sources of RS+. They are used in the formation of RS-N and RS-O bonds....
s. SO2Cl2 can also convert alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s to alkyl chlorides. In industry, sulfuryl chloride is most used in producing pesticides.
SO2Cl2 can also be used to treat wool to prevent shrinking.
Precautions
SO2Cl2 is toxic, corrosive, and acts as a lachrymatorLachrymatory agent
Tear gas, formally known as a lachrymatory agent or lachrymator , is a non-lethal chemical weapon that stimulates the corneal nerves in the eyes to cause tears, pain, and even blindness...
. As described above, it can form explosive mixtures with water, as well as donor solvents such as DMSO
Dimethyl sulfoxide
Dimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...
and DMF
Dimethylformamide
Dimethylformamide is an organic compound with the formula 2NCH. Commonly abbreviated as DMF , this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions...
.